The AA said that while Communities Minister Eric Pickles is reining in local authorities who over-zealously use CCTV, private parking operators now rely heavily on this technology and automatic number plate recognition (ANPR) to watch drivers and issue tickets through the post when they put a foot wrong in parking areas.

It added that there had been a surge in the number of parking charge notices issued by private firms through the post with complaints coming in from Edinburgh to the south coast of England.

"With clamps no longer an option now in England and Wales it was inevitable that the number of parking charge notices (private parking tickets) would increase," the AA said.

It said the increasing number of complaints it received had exposed "a new and hard-line attitude by private enforcement firms".

Recent cases included harsh treatment of a diabetic who slept slightly beyond the two-hour limit at a deserted motorway service area in the early hours after having concerns about his blood sugar level.

Despite obtaining a doctor's certificate, his appeal was rejected by the parking firm, which also said he could pay the £60 by monthly instalments although he said this would cause hardship.

Another AA member in London was threatened with a £160 parking ticket which breached the £100 maximum recommended by the British Parking Association's code, to which the enforcement firm was signed up. She was so scared she paid up rather than taking the case to the new independent appeal service POPLA.

The AA said POPLA appeared to be struggling to cope with appeal demand with its website warning of high demand and a back log.

It added that one AA member who was wrongly clamped and towed in 2012 secured a victory against the clamper in court. But despite employing his own bailiff to recover the sum he has yet to see a penny of the £500 he was awarded because the clamper has gone to ground.

AA president Edmund King said: "We are pleased that after decades of clamper extortion their practices have largely been consigned to history.

"However, private parking enforcement remains unregulated and is a free-for-all when even firms signed up to a code of practice breach their own rules. It seems many of the notorious clampers have moved their sharp practices to private parking enforcement."